Jam Heine wrote:In part 2 of our series ’12 Myths in Cycling,’ we’ll look at why titanium isn’t always lighter than steel. I can hear you saying, “What? Everybody knows that titanium has half the density of steel.”

That much is true: The same part made from titanium will weigh half as much as the equivalent from steel. But titanium has only half the stiffness, so the part will be half as stiff. To make the parts of the same stiffness, you need to use twice as much material with titanium, and the weight will be equal. The same applies to aluminum, which is one-third as heavy and one-third as stiff. (These numbers are for the high-strength alloys; raw aluminum, titanium and iron are not strong enough to be used for cycling applications.)

As anyone who's done first year "statics and dynamics" and "strengths of materials" will know, anything less than about 300 pages is an oversimplification of most use cases. And that's before we get into tribiology or corrosion.

hamishm wrote:It's funny to see such a bunch of irrational haters too.

Hater? No, but when his blog has complete propaganda like the following, you can see why some people roll their eyes:

The excellent performance of the Compass tire shows once again why wide tires have revolutionized cycling: You wouldn’t want to ride the other tires on TOUR’s list on anything but the smoothest, cleanest roads for fear of flats and premature wear. And yet with wider tires, we can ride some of the world’s fastest tires on the backroads where cycling is at its most beautiful.

Good grief, talk about hyperbole. I've used those Continental tyres his blog has written off there for years and years and had no troubles with flats or premature wear on them. I get heaps of distance on them.

Next he'll be saying that heavier bikes are faster uphill than light ones, and I'm sure he'll pull some figures out of the air to support it, mixed in with pages of writing.

Yes, we all know that he's straight out of the Thomas Edison tradition of American-style marketing.

However, to date, there's been nothing wrong (that I know of) with these threads.

One my points in posting them is to see whether there are any recent countervailing data or studies. (Fire away, folks)

Now I am aware of some commentators having issues with the not-entirely-scientific-textbook methods he uses for testing. However, so far, without providing better quality counter examples.

I am also aware of one forum member having problems with tubeless tyres blowing off and being very unhappy with the response from Compass.

Disclaimers: I went to wide tyres and mudguards long before I had even heard of Jan Heine. And I don't own anything sold by his brands.

It's the near straight out propaganda that I object to:

The excellent performance of the Compass tire shows once again why wide tires have revolutionized cycling: You wouldn’t want to ride the other tires on TOUR’s list on anything but the smoothest, cleanest roads for fear of flats and premature wear. And yet with wider tires, we can ride some of the world’s fastest tires on the backroads where cycling is at its most beautiful.

Good grief, talk about hyperbole. I've used those Continental tyres his blog has written off there for years and years and had no troubles with flats or premature wear on them.

Next he'll be saying that heavier bikes are faster uphill than light ones, and I'm sure he'll pull some figures out of the air to support it, mixed in with pages of writing. It's all just marketing bluff anyway designed to sell his products.

The excellent performance of the Compass tire shows once again why wide tires have revolutionized cycling: You wouldn’t want to ride the other tires on TOUR’s list on anything but the smoothest, cleanest roads for fear of flats and premature wear. And yet with wider tires, we can ride some of the world’s fastest tires on the backroads where cycling is at its most beautiful.

Good grief, talk about hyperbole.

So, let's cut to the chase: there's two points here1. It's marketing copy. Fine, no different to the crap in any other magazine/website. Trim that away and we get to

2. His thesis is: that wider tyres allow lower pressures which result in less punctures, in this case from (sharp) gravel on unmade roads.

I'm interested in any response to that. Preferably in the wide tyre thread.

It is significantly stronger than the most commonly used grades of steel. As others have noted, the strongest known alloy steels in their strongest tempers are stronger than the strongest titanium alloys in their hardest temper.

That said, the most commonly used alloy of Titanium (6al4v) is significantly stronger than the most commonly used steels.

As others have pointed out, Titanium is remarkable for its strength, given its weight. It is also remarkable for its amazing resistance to corrosion.

Comedian wrote:Interesting.. not my understanding... Kind of makes you wonder why it's the go-to material for very high load aerospace applications given it's cost and manufacturing difficulty ..

I think the temperature resistance was one reason to go for it in the SR-71, among others (although it also used composites in some areas). It's also susceptible to damage from some chemicals, even those you might find in water (to kill bugs in town water supplies), as Kelly Johnson and his team discovered to their horror when developing the A-12/SR-71.

I'd have to go back to the notes I have from some of the AIAA lectures, but from memory titanium isn't really the go to material as much as it was now (at least not for high temperature leading-edge uses). Admittedly we are talking between 1800-2000°C here.

Thoglette wrote:So, let's cut to the chase: there's two points here1. It's marketing copy. Fine, no different to the crap in any other magazine/website. Trim that away and we get to

2. His thesis is: that wider tyres allow lower pressures which result in less punctures, in this case from (sharp) gravel on unmade roads.

I'm interested in any response to that. Preferably in the wide tyre thread.

No issue with that. However above a moderate speed aerodynamic losses from wide >28mm tyres are going to render them slower than the narrower tyres as the modest improvement in rolling resistance is cancelled out by the larger increase in aero drag. Any number of threads already covering this subject.You can also chose to ride Marathon plus and the like if puncture resistance is your sole target, They ride like cr@p though.

It is significantly stronger than the most commonly used grades of steel. As others have noted, the strongest known alloy steels in their strongest tempers are stronger than the strongest titanium alloys in their hardest temper.

That said, the most commonly used alloy of Titanium (6al4v) is significantly stronger than the most commonly used steels.

As others have pointed out, Titanium is remarkable for its strength, given its weight. It is also remarkable for its amazing resistance to corrosion.

Yeah I still generally filter Heiney out too. lolThanks for confirming why.

Comedian wrote:Interesting.. not my understanding... Kind of makes you wonder why it's the go-to material for very high load aerospace applications given it's cost and manufacturing difficulty ..

I think the temperature resistance was one reason to go for it in the SR-71, among others (although it also used composites in some areas). It's also susceptible to damage from some chemicals, even those you might find in water (to kill bugs in town water supplies), as Kelly Johnson and his team discovered to their horror when developing the A-12/SR-71.

I'd have to go back to the notes I have from some of the AIAA lectures, but from memory titanium isn't really the go to material as much as it was now (at least not for high temperature leading-edge uses). Admittedly we are talking between 1800-2000°C here.

Interestingly ... from wikipedia on the boeing 787...

Boeing lists its materials by weight as 50 percent composite, 20 percent aluminum, 15 percent titanium, 10 percent steel, and 5 percent other.[182][183] Aluminum has been used throughout the wing and tail leading edges, titanium is predominantly present within the elements of the engines and fasteners, while various individual components are composed of steel.

If I remember.. when they did the SR-71 the US didn't actually have a source of Titanium in the quantities that were required.. so they got it from the ruskies.

Titanium was in short supply in the United States, so the Skunk Works team was forced to look elsewhere for the metal. Much of the needed material came from the Soviet Union. Colonel Rich Graham, SR-71 pilot, described the acquisition process:

"The airplane is 92% titanium inside and out. Back when they were building the airplane the United States didn't have the ore supplies – an ore called rutile ore. It's a very sandy soil and it's only found in very few parts of the world. The major supplier of the ore was the USSR. Working through Third World countries and bogus operations, they were able to get the rutile ore shipped to the United States to build the SR-71."

I guess I wouldn't say I am an acolyte, but I tend to agree with him on most things.

Most of the stuff the cycling industry is marketing is based on unpublished pseudoscience. Nothing really any different to Jan.

Most cyclists think they are racers and so believe they need the latest and greatest speed weaponry even though for the majority of their riding they are lucky to average 30 km/hr.

I certainly know I am no racer and enjoy the benefit of wider pressure tyres at lower pressure. Because I want comfort and grip and the roads around my place are crap.

I will not use a saddle bag again after I started mounting my bag on the front, it is so much better for climbing out of the saddle.

I have broken all frame materials in the past but for me the most reliable has been steel. And I have to say that best riding bikes I have ever ridden are standard diameter steel frames and forks built with high quality steel from Renyolds, Tange and Columbus.

Jam Heine wrote:In part 2 of our series ’12 Myths in Cycling,’ we’ll look at why titanium isn’t always lighter than steel. I can hear you saying, “What? Everybody knows that titanium has half the density of steel.”

That much is true: The same part made from titanium will weigh half as much as the equivalent from steel. But titanium has only half the stiffness, so the part will be half as stiff. To make the parts of the same stiffness, you need to use twice as much material with titanium, and the weight will be equal. The same applies to aluminum, which is one-third as heavy and one-third as stiff. (These numbers are for the high-strength alloys; raw aluminum, titanium and iron are not strong enough to be used for cycling applications.)

As anyone who's done first year "statics and dynamics" and "strengths of materials" will know, anything less than about 300 pages is an oversimplification of most use cases. And that's before we get into tribiology or corrosion.

....attended and got given a degree in metallurgy - was expecting a merit in rock climbing and bouldering...pursued the climbing post grad' but never took up becoming a proper chartered engineer so my knowledge of balance sheets is better than that of phase diagrams....saving 300pages will try for 1 sentence - Stiffness is not the same as strength. (full stop!)

The lower stiffness (measured by Youngs Modulus) of Ti Alloys to Steel and Al' alloys is what gives Ti bikes a more pleasant feel for all day riding - of course bad design can screw over any mechanical properties - for stiffness v strength a quick google gives this easy to read article:

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